The present disclosure relates to a filler neck closure assembly for a vehicle fuel tank, and particularly to a filler neck closure for use in a capless fuel tank filler neck. More particularly, the present disclosure relates to closure seals and to pressure/vacuum-relief valves for use in a filler neck closure assembly.
A removable fuel cap with a sealing gasket is typically used to close the open end of a fuel tank filler neck. After an attendant fills the fuel tank and withdraws the pump nozzle from the filler neck, the fuel cap is attached to the filler neck so that the sealing gasket forms a seal between the fuel cap and the filler neck. Thus, the fuel cap closes the open end of the filler neck to block discharge of liquid fuel and fuel vapor from the fuel tank through the filler neck. Some fuel caps are provided with pressure-relief and vacuum-relief valves to permit some controlled venting of fuel vapors in the filler neck, while the fuel cap is mounted on the filler neck.
It has been observed that fuel caps are often lost or damaged over time and, as a result, the open end of the filler neck might not be closed and sealed in accordance with original equipment specifications during operation of the vehicle. Accordingly, a filler neck configured to “open” automatically as a fuel-dispensing pump nozzle is inserted into the filler neck during refueling and “close” automatically once the pump nozzle is withdrawn from the filler neck without requiring an attendant to reattach a fuel cap to the filler neck would be an improvement over many conventional capped filler neck systems. Although conventional fuel caps function to close filler necks in a satisfactory manner, it is thought that a capless filler neck could make vehicle refueling more convenient for consumers because no action other than inserting a pump nozzle into the outer end of the filler neck would be required to begin refueling a vehicle.